Добавил:
Sekretar
kiopkiopkiop18@yandex.ru
t.me/Prokururor I Вовсе не секретарь, но почту проверяю
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз:
Предмет:
Файл:Ординатура / Хирургия / Библиотека им академика М.И. Перельмана / Книга_3753_Библиотеки_им_академика_М_И_Перельмана
.pdf
Transoesophageal Echocardiography for Safe Endoscopic Cardiac Surgery 49
Video 6 TOE post bypass (▶ https://doi.org/10.1007/000-a79)
References
1. Hahn RT, Abraham T, Adams MS, et al. Guidelines
for performing a comprehensive echocardiographic
examination: Recommendations from the American
society of Echocardiography and the Society of
cardiovascular anaesthesiologists. J Am Soc Echocardiogr. 2013;26:921–64.
2. Purza R, Ghosh S, Walker C, Hiebert B, Koley L,
Mackenzie S, et al. Transesophageal echocardiography complications in adult cardiac surgery: a retrospective cohort study. Ann Thorac Surg. 2017;103:
795–803.
Endoscopic Conduit Harvesting: Best
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Practice Training Guidelines
Bhuvaneswari Krishnamoorthy
and Jared Blackmore
Abstract
The great saphenous vein rema ins the most
commonly used conduit for non-left anterior
descending coronary artery bypass graft
surgery. The aim of this chapter is to define
the best practice training standards for use of
the Endoscopic Vein Harvesting (EVH) technique during coronary artery bypass surgery.
This chapter has been collated by an international multidisciplinary panel of advanced
practice providers, surgeons, cardiologists
and anaesthetists with common interests and
expertise in caring for patients with coronary
artery disease. These proposed training standards have been developed using current best
evidence and from experiences of those most
closely involved in the process, with proposals
receiving approval for recommendation by
consensus. A total of 11 criteria for best
training practice were defined including recommendations on patient selection , surgical
training, ultrasound vein scanning, heparinisation, diathermy settings, CO
and setting, training/volume threshold, harvesting with minimal surrounding tissues, use
of pressure-controlled syringe for vein disten-
B. Krishnamoorthy (&) J. Blackmore
The University of Salford and Manchester
Foundation Trust, Manchester, England, UK
e-mail: b.bibleraaj@salford.ac.uk
insufflation
2
sion and the need for regular audit. The team
agrees that EVH is a standard practice in
USA, however in the rest of the world there
still remains a reticence about EVH due to
concerns about the quality of the vein and cost
of equipment. There are lots of differences in
harvesting practices between USA and the rest
of the world due to there being no documented
and accepted standards of EVH best practice.
The main aim of writing this chapter was to
produce a resource to which all EVH trainee
practitioners can refer. We hope it will provide
the first set of standards and promote safe
practice by surgical colleagues to ensure high
quality conduits are retrieved and prevent
harm to the patient during training.
Keywords
Endoscopic conduit harvestingBest practice
guidelines
Standardisation
1 Introduction
Coronary Artery Bypass Grafting (CABG)
remains the gold standard surgical procedure to
relieve the symptoms and provide long term
prognosis in multivessel coronary artery disease
[1]. In spite of evidence that multiple arterial
grafts provide better long-term patency rate [2,
3], the Greater Saphenous Vein (GSV) is the
© The Author(s), under exclusive license to Springer Nature Switzerland AG 2023
J. Zacharias (ed.), Endoscopic Cardiac Surgery,
https://doi.org/10.1007/978-3-031-21104-1_4
51
52 B. Krishnamoorthy and J. Blackmore
most commonly used supplementary conduit
with the left internal thoracic artery grafted to the
left anterior descending coronary artery, with
more than 90% of coronary bypass surgery
conducted with GSV [4–6]. Open vein harvesting has been the standard technique for harvesting GSV conduits for bypass surgery since 1950.
However, open vein harvesting is associated with
a high incidence of postoperative leg woun d
complications and morbidity [7]. In an attempt to
reduce postoperative pain, lower wound complication rates and improve patient satisfaction,
the Endoscopic Vein Harvesting (EVH) technique was developed and introduced to clinical
practice in mid-1990 [8, 9]. In the USA,
approximately 90% of CABG patients receive
EVH as a standard of care but in other parts of
the world there is still significant practice variability and debate about the quality of the conduit
and long-term patency when using the EVH
approach [7, 10–13].
The International Society for Minimally
Invasive Cardiothoracic Surgery (ISMICS) 2017
consensus statement recommends that EVH
should be the standard of care (class I, level B),
to reduce the wound related complications (class
I, level A), to improve patient satisfaction and
postoperative pain (class I, level A), to reduce the
postoperative length of stay and outpatient
wound management resources (class I, level A)
and the quality of conduit harvested (class IIa,
level B-R) [14]. Furthermore, the ISMICS panel
concluded that the rigorously analysed, high
quality evidence demonstrates no increase in
major adverse cardiac events or decrease in graft
patency for endoscopically harvested saphenous
vein [14]. Unfortunately, this consensus statement has failed to allay the fears of non EVH
users regarding the quality of harvested vein and
long-term patency rates [15, 16].
Over the past 10 years multiple publications
have looked at medium- and long-term outcomes
of patients who have had endoscopic vein harvesting against open vein harvesting [17–19]. No
long-term registry has shown adverse outcomes
among patients with EVH against OVH. Despite
this there remain concerns of graft patency in a
subgroup analysis of a Randomised Control Trial
(RCT) ([20 ] which have raised some questions
that can only be answered by an adequately
powered RCT looking at graft patency over time.
As most patients and funders are more interested
in quality of life and survival among patients this
trial may never be funded, and we may have to
continue to rely on real world registry data. If
EVH surgery is to become routine standard of
care for CABG surgery, the harvesting technique
should be exposed to close scrutiny to safeguard
that the highest standards of pract ice are
achieved.
The delivery of surgical care in moder n
healthcare systems is rapidly evolving into a
multidisciplinary approach with increased
involvement of more specialised staff for each
point of intervention in order to provide best
possible care to all service users [21]. To desig n,
understand and set the best practice standards for
endoscopic vein harvesting, we have utilised a
multidisciplinary team approach. Due to the
paucity of proposed stand ards in cardiac surgery
for vein harvesting, this best practice training
standards chapter was produced using the existing best practice model for mitral valve repair as
a template [21].
2 Methods
The training standards were developed and
assessed using all the data assembled from the
existing literature followed by discussion by a
group of multidisciplinary panel members to
achieve an agreement. The panel members were
selected for their expertise in EVH harvesting,
bypass surgery and caring for CABG patients.
The following questions were asked to set proposed standards of EVH practice:
1. What institutional and local criteria are
required to achieve best EVH practice during
training?
2. Are there any local guidelines for EVH best
practice?
3. What clinical outcomes are expected after leg
vein harvesting surgery?
Endoscopic Conduit Harvesting: Best Practice Training Guidelines 53
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
4. Is it feasible to define training standards for
best practice for EVH by a multidisciplinary
panel agreement?
5. Are there any identifiable criteria for selecting
EVH as the vein harvesting technique or can
the EVH be applied universally to all
patients?
6. Do we need to monitor trainees in order to
minimise/avoid damage that may have an
impact on the quality of the vein?
7. Is it possible to set a threshold for training
requirements and caseload volume for best
practice?
3 Results
To develop best surgical training standard
guidelines, it is vital that initial criteria proposals
are set out by experienced surgical colleagues
and practitioners. A total of 10 recommendations
were made by the panel from their experience of
what was required to retrieve a vein conduit of
quality equal to that achieved with the current
standard open vein harvesting technique. These
key recommendations involved:
training period. Patients with conditions such as
diabetes mellitus, peripheral vascular disease and
diseased veins (previous incidence of superficial
thrombophlebitis) may be predisposed to accelerated myointimal proliferation which leads to
luminal narrowing and early occlusion of the
vein graft [22, 23].
Patients with varicose veins have vein walls
that are thin and inelastic and consequently have
high risk of rupture compared to normal veins
[24]. Similarly, patients with thin legs and/or
superficial veins have the possibility of more thin
hair line branches. This poses a higher risk for
avlusion at the base of the vein branch during
EVH [20]. Any trauma during harvesting in these
patients with co-morbidities is likely to accelerate vein stenosis in the long-term. Indeed, any
damage to the fragile thin GSV endothelium
appears to be a key promotor for the development and progress of vein graft disease, stenosis
and complete failure [25].
3.2 Contraindications for EVH
and Rationale
– Patient selection
– Surgical training
– Ultrasound scanning of the GSV before
surgery
– Heparinisation
– Diathermy settings
– CO
insufflation and setting
2
– Training and volume threshold
– Harvesting with minimal surrounding tissue
– Use of a pressure-controlled syringe
– Use of vacuum suction leg drain
– Auditing routine practice to benchmark
against other hospitals.
3.1 Patient Selection
The panel believes that there should be a criterion for selecting patients both during and following successful completion of the EVH
• EVH should not be performed by novice
practitioners during ongoing ischemia necessitating an emergency CABG due to the
duration of vein harvest and risk for conduit
damage. However, if the practitioner is experienced and has shown the ability to expeditiously harvest a quality conduit, it would be
appropriate to utilise EVH during an emergency CABG.
• Superficial GSV (<1/2 cm below the skin)
should be avoided due to spatial limitations
for the operator between the skin and vein.
The EVH cannula shaft external diameter is a
further consideration, being approximately
1.5 cm (Maquet Vasoview Hemopro™)or
greater from some other companies. It is
important not to insert the scope forcefully as
this may damage the adventitial layer of the
vein which causes localised bruising and
haematoma inside the layers of the vein [26].
This additional trauma caused by the
54 B. Krishnamoorthy and J. Blackmore
harvesters can accelerate the natural progression of graft degeneration leading to early
graft occlusion.
• Varicose veins are thin-walled vessels characterised by a loss of elasticity and the presence of
numerous vein bulbs. This is associated with a
high risk of rupture during harvesting when
compared to normal veins [27]. There are many
factors that can significantly affect graft
patency in CABG surgery. However, patients
with saphenofemoral incompetency or thrombophlebitis of superficial veins can increase the
risk of poor graft quality and subsequently
affect its patency. Many histological studies
have illustrated that the varicose veins have
intimal hypertrophy, subendothelial fibrosis,
luminal dilation and wall thickening [27–30].
These varicose veins have persistent venous
hypertension, chronic inflammation and
genetic variations that alter the vessel wall of
the GSV. As such, it is good practice to avoid
harvesting these veins by EVH. Experienced
practitioners can harvest the patients with
minimal varicose veins with maximum care.
• Patients with small or thin legs (<7.5 cm
diameter at the lower calf) determined via an
ultrasound scan [31] should not have veins
harvested using the EVH technique. These
veins tend to have more superficial hair line
branches which are highly likely to be torn
from the base of the vein during harves ting.
However, some argue that performing fasciotomy on these patients can open up the
space between the skin and the vein yet still
there remains a high risk of vein bruising and
vein/branch tear [22, 26]. Again, it is important for the EVH trainee practitioner to assess
the situation carefully and take decision to
harvest suitable conduit for the surgery.
4 Ideal Patients for EVH Training
It is the opinion of the panel that novice practitioners should avoid the most technically challenging patients (those with venous comorbidities, BMI above 35, peripheral vascular
disease and muscular patients) during their
training period. By doing so, novice practitioners
can focus on implementing their learned skills
and obtaining good quality veins for CABG
surgery without unnecessary stress. For at least
their first 25 cases, novice trainees should harvest
veins from patients with good quality veins as
confirmed by ultrasound. The trainees should be
taught gradually, initially harvesting one length
of vein starting with few dissections and few
branches. Only once proficient with a single
length of good quality vein should the practitioner moved to two or more lengths of vein. The
final stage of training should incorporate more
complex cases such as female patients and obese
patients. This way, novice practitioners can
accelerate their learning curve [22, 32, 33] rather
than struggling with difficult cases early on,
which can impact upon the practitioner’s confidence. It can potentially reduce the perception
that EVH technique is responsible for poor
quality veins with worse long-term outcomes.
4.1 Surgical Training for EVH
Training modalities vary depending on region
and country. In the UK, the previous standard
requirement was an in-house training which led
to a diploma in cardiothoracic surgery. These
practitioners were then trained in-house on how
to assist and perform open vein harvesting.
However, in 2014 the Department of Health in
UK published a Surgical Care Practitioner
(SCP) curriculum, which made a Masters in
Surgical Practice a recognised academic national
qualification for all SCPs. This way the SCPs
undergo rigorous academic and speciality training for two years in a UK academic institute
which covers the pre, intra and postoperative care
pathway of a patient. For international EVH
practitioners, they should follow their local
academic/institutional training programme. In the
USA and other parts of the world, these surgical
team members can be referred to as Physician
Assistants, Surgical Assistants, Certified Registered Nurse First Assistants or Nurse Practitioners depending on the training.
Endoscopic Conduit Harvesting: Best Practice Training Guidelines 55
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
In-house training of practitioners to perform
specific jobs is no longer common practice. It is
vital for members of the surgical team to be
educated to a consistently higher level of skill
and knowledge to deliver high quality patient
care. The practitioners who work in a surgical
team should have basic knowledge and understanding of the anatomy and pathophysiology of
a disease condition, its differential diagnosis and
management pathway. Importantly, practitioners
must also be comfortable working as part of a
large multidisciplinary team.
During training, junior surgeons and junior
practitioners shoul d be exposed to the standard
open vein harvesting of 10 cases (depends upon
individual manual dexterity) to gain knowledge of
vein harvesting and the importance of vein
preservation for conduit surgery. Exposing trainees too soon to EVH can yield poor quality vein
conduits. This is because the EVH technique
requires good hand-eye co-ordination with psychomotor technical skills to operate the EVH
equipment [22]. Many studies have concluded
that experienced practitioners obtain good quality
veins due to the skills they acquired during their
prolonged experience [22, 34]. It is important to
have a standardised and structured training curriculum for the EVH trainees to accumulate the
skills and the theoretical knowledge required to
obtain the best quality vein conduit [31, 35]. The
panel believes that the length of skin incision for
harvesting the vein is in itself not as important as
preserving its integrity and obtaining better quality of conduit, which is vital for the patient to
ensure graft patency for a number of years to come
[36]. However, this can be argued by the high
volume EVH centres across the world that they
teach their practitioners only EVH not traditional
open vein harvesting technique. It should be
considered as a local preference and these centres
should collect their local data to compare the
quality of the vein with experienced practitioners.
4.2 Structured Training
The quality of the vein harvested by novice
practitioners remains questionable due to their
lack of familiarity with the EVH technique and
lack of endoscopic skills [37]. It is important to
devise a structured training curriculum to improve
the theoretical and practical knowledge of the
novice EVH practitioners [26]. The departments
can devise their own style of teaching method
using Manchester Endoscopic Learning Tool
(MELT) [26] training model to guide their trainees through EVH (Fig. 1). Minimising vein
trauma can improve the surgeons’ confidence
with the endoscopic procedures and also provides
good quality veins as conduits for the patient. The
inexperience of the novice practitioners can
increase the risk of vein trauma and denudation of
the endothelium which gradually leads to vein
graft failure [26, 38]. Furthermore, appropriate
teaching of novice trainers will help alleviate the
stress of learning. Competency based e-learning
theoretical modules that continually reinforce the
importance of vein preservation, provide anatomy
and physiology knowledge, and walk through the
steps of the EVH surgical procedure should form
the core of the initial training.
5 E-Learning Theoretical Module
As we are in the twenty-first century with wide
access to technologies for teaching purposes, it is
vital that we take advantage of this and utilise the
e-learning platform for teaching the EVH technique outside of the theatre. It is not possible for
the trainer to transfer all knowledge to the trainee
within the theatre environment. Learning within
the theatre can be very difficult and creating a
conducive environment is important for the trainee to learn in a stress-free environment [39].
There is no currently available e-learning
based module or accredited programme for EVH.
The EVH equipment has been modified many
times by the surgical companies to obtain
improved quality veins. It is vital that the EVH
product companies spend time and effort on
producing these educational tools in order to
ensure the best possible trainee experience,
which may allow an acceleration of the learning
curve and reduce the incidence of poor-quality
conduit during the learning phase.
56 B. Krishnamoorthy and J. Blackmore
Fig. 1 This schematic diagram illustrating an overview of the MELT [26] training regimen
assessment prior to vein harvesting can therefore
6 Vein Doppler Ultrasound
Mapping
Traditionally, ultr asound vein assessment is carried out for cardiac surgery patients with varicosities clinical indications of potentially poor
vein conduits and history of vascular diseases
[16]. However, the recent UK National Institute
of Clinical Excellence 2014 guidelines rightly
insist that all patients who undergo vein harvesting for CABG surgery should undergo
ultrasound mapping to identify the quality, size,
depth (Fig. 2), placements (Fig. 3) and anatomical variations of the GSV. The use of ultrasound
by the anaesthetist for insertion of the central
venous line has become mandatory and it is
readily available with low cost to the theatre
department. The use of these machines for GSV
help the EVH practitioner to understand the
depth of the vein and where to make the skin
incision. It can also identify the size of the vein
and any abnormalities. GSV anatomical variations can range from 20 to 40%, which can be
easily detected by the ultrasound guided scan and
this helps the practitioner to plan the surgical
technique and pick the appropriate leg [40].
Studies have demonstrated that the scanning of
veins prior to coronary surgery minimises unnecessary surgical skin incisions, reduces the risk of
postoperative wound complications, particularly
in female, obese and diabetic patients, and allows
accurate prediction of the anatomy and size of the
harvested veins. They have also concluded that the
use of ultrasound by the practitioners/surgeons in
theatre prior to surgery or the day before surgery is
feasible, simple, and reduces the surgical harvest
Endoscopic Conduit Harvesting: Best Practice Training Guidelines 57
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
Fig. 2 Illustrates the vein doppler scan with the long saphenous vein on the transverse section
Fig. 3 Illustrates the longitudinal vein doppler scan of the long saphenous vein
58 B. Krishnamoorthy and J. Blackmore
time, is cost effective and diminishes postoperative morbidity [16, 40–43].
The use of a vascular lab scientist to scan each
and every cardiac surgery patient can be very
expensive, and as such this needs to be audited
and a cost analysis performed. In order to minimise the cost impact of scanning each patient,
the SCPs who are trained to work as part of the
surgical team in cardiac theatres should take the
role of routine ultrasound scanning of the veins if
no additional co-morbidities are present. This
will also be beneficial in reducing the pressure
and workload of the vascular scientist. However,
this panel suggests that the patients with severe
varicosities, peripheral vascular disease and
clinical signs of poor vein conduits need to be
sent to the vascular department for detailed
scanning including radial artery perfusion scanning. There should be a national protocol/
guideline on how to scan, when to scan and
when to refer the patient to the vascular department in order to prevent increased costs and
unnecessary delays in most patients.
Importantly, there are no accredited vein
mapping courses for SCPs in Great Britain to
teach the basic theoretical knowledge, hands on
practical skills and competency curriculum
which need to be devised as a matter of urgency.
It is important to teach practitioners these skills
in a structured competency-based curriculum for
patient and practitioner safety. We believe that
in-house training on how to scan needs to be
stopped and an agreed curriculum developed to
deliver a high standard educational programme.
7 Importance of Heparinisation
Prior to EVH Technique
All EVH surgical patients need to be heparinised
as part of the best surgical practice. The veins
taken by endoscopic surgery are at high risk of
developing micro intraluminal clots inside the
vein lumen [44]. Studies performed without preheparinisation have demonstrated a nonsignificant trend towards reduced patency of the harvested GSV, which may be due to intraluminal
clot formation [45, 46]. The heparin should be
given intravenous once the vein is identified and
at least five minutes before starting the vein
dissection. According to Brown et al., preheparinisation did not change blood loss or
transfusion requirements but the experience of
this panel is different. The use of 5000 units’
heparin for all patients without exclusion can
increase blood loss during sternotomy and
internal mammary artery harvesting. Each panel
members have experience of at least 1000 cases
of EVH, with some members having performed
over 3000 cases. Our recommendation would be
to provide a lower (2500 units) dose to patients
who have been receiving antiplatelet medications
until the day before surgery to avoid risk of
bleeding and haematoma formation. Patients who
have stopped the use of anticoagulants as part of
normal local practice seven days prior to the
surgery should be administered 5000 IU of
heparin systemically to avoid intraluminal clots
in the harvested vein [31, 35, 44].
7.1 Diathermy Settings
Most surgical procedures use diathermy, which is
the process of using electricity to produce cauterisation burn at the point of contact [47]. In the
infancy of endoscopic surgery, bipolar diathermy
was considered as an accurate control of the
electric current by limiting the thermal spread
into the surrounding tissues. However, the new
latest technologies such as the Harmonic Scalpel™ (Ethicon, Endo-surgery, Cincinnati, Ohio,
USA) and Ligasure™ (Valleylab, Boulder, Colorado, USA) are better than the traditional
bipolar diathermy for many endoscopic surgeries
[48, 49]. The Hemopro™ diathermy system has
the same effect as Harmonic Scalpel™, which
has a generator, an ultrasonic transducer and an
instrument. This system produces ultrasonic
energy which directly controls the bleeding
through the process of coaptive coagulation
which allows cut-and seal without thermal spread
[24]. In contrast, the Ligasure utilises a mixture
of pressure and current to melt the collagen and
elastin comprised within the blood vessel walls
and then seals the vessels [24].
Endoscopic Conduit Harvesting: Best Practice Training Guidelines 59
Данная книга находится в списке для перевода на русский язык сайта https://meduniver.com/
In the EVH surgical procedure, the bipolar
and Hemopro diathermy systems are used. From
the introduction of EVH equipment in the mid1990s, there are many instances in the literature
of surgeons concerned about the intimal electrocautery damage mainly due to thermal spread
into the intima. If we look at the different
equipment available between1990 and now,
company product research has evolved to make
single handed equipment instead of multiple
different items. This is a significant improvement
as it minimises the risk of damage to the vein due
to repeated insertion of multiple instruments to
harvest the vein endoscopically.
The bipolar diathermy EVH system requires
the application of electrosurgical energy which is
always controlled by a foot switch. The harvester
needs to be very careful especially on EVH
technique to make sure that there is enough
length left on the side branches from the base of
the vein to avoid any damage caused during
cauterisation. Leaving at least 1 cm branch
length from the base of the vein will prevent
thermal spread to the main conduit. However,
there has been no study performed to evaluate the
extent of the thermal spread from the bipolar
cautery tip to the base of the vein in patient
samples. A porcine study comparing the spread
of heat on monopolar, bipolar, harmonic scalpel
and ligasure concluded that there is no change of
temperature more than 1 cm from the tip of the
instrument [47]. Until more definitive data is
collected from thermal studies on the vein, the
panel believe that it is best practice to keep more
than 1 cm distance from the base of the vein
branch to avoid heat and thermal spread.
Intriguingly, only one company (Getinge™)
[50] has mentioned that their equipment uses inline instrumentation with strategies to mitigate
thermal spread by using Hemopro 2 technology
which seals the vein with cut in a single
step. Their Hemopro 2 simultaneous cut-and-seal
technology virtually eliminates the thermal
spread beyond the device. There is also a safety
system inbuilt so that the Hemopro 2 system does
not produce any heat or shorten branches which
consequently preserves the integrity of the harvested vein [51]. However, there is no histological study to determine the effect of thermal
spread on harvested veins.
From the collective panel, who hav e the
experience of performing more than 5000 EVH
procedures, the recommendation is to set the
Hemopro diathermy between 2 and 2.5 [31]in
order to avoid any burning and cause minimal
damage to the small/thin hairline branches. The
use of Hemopro 2 until release of resistance
followed by visual confirmation of branch and/or
connective tissue ligation is signi ficantly better
practice than pulling or intermittent diathermy
use. The Getinge™ EVH user manual [50] recommendation of setting at 3 and above is too
much for any GSV branches unless you have a
duplicate GSV with diameter greater more than
0.4 cm on the ultrasound. The other companies
using bipolar diathermy for EVH recommends
around 15 W to 30 W [52]. However, in order to
reduce the thermal damage to the vein, 10 W
might be better.
This area needs to be explored in more depth
as a multicentre randomised control trial to
determine the optimal device and settings for
future use.
7.2 CO2Settings and Insufflation
Most of the EVH systems utilise CO2insufflation
(open or closed tunnel) as a method to create a
subcutaneous tunnel for tissue dissection and for
clear visualisation [35, 53]. The insufflation helps
to create a subcutaneous tunnel which directly
facilitates the harvesting of the GSV without
working close to the vessel. The insufflated CO
is normally absorbed by the blood stream and
eliminated by the lungs [54]. However, the
insufflation can cause CO
embolism and
2
hypercarbia via absorption through an injured
GSV. If the CO
enters directly into the blood
2
stream, it can result in the stimulation of the
sympathetic nervous system [35, 52]. These lifethreatening events are very rare in cardiac
2
Соседние файлы в папке Библиотека им академика М.И. Перельмана